I’ve been waiting and waiting and waiting.
“xBook” is my designation, coined here:
Since people cannot decide whether they are “enhanced” or “enriched” or “eBooks with extras,” I am coining the term xBook to encompass digital books that contain audio, video, and other interactive elements that require more than an eInk device to read. xBook has the advantage of not being a widely-known trademark and the “x as extra” is easy to explain to people. (Western Skyland Corporation holds a trademark for “xBook.” Western Skyland Corporation is a beard company for Microsoft. Since all but one other trademark held by this beard company is dead, I think it’s safe to use xBook as a generic term since it is not being actively used in the marketplace by the registrant.) Note that xBook should refer to an eBook — ePub or Kindle format — with extras, not an app, such as Vook.
What I didn’t know then was that Apple was part of the IDPF and waiting for the ePub3 spec to be finalized.